Maths on the Move

Welcome to the latest episode of Maths on the Move! In this episode we spoke to Cambridge Professor of Theoretical Physics Ulrich Sperhake and his graduate student, Seppe Staelens, about boson stars: hypothetical objects that might be masquerading as black holes.

Our conversation with Ulrich and Seppe marked the tenth anniversary of the first detection of gravitational waves. As Ulrich explained back then, gravitational waves "opened our ears to the Universe in a waveband in which we have been 100% deaf up to now" and they also help us understand black holes and boson stars. In this podcast Seppe and Uli explain more, taking us to the frontiers of current research..

To find out more about the topics discussed in this podcast, you might like:

A short explainer of gravitational waves

Gravitational waves reveal cosmic hum: another podcast with Ulrich

Dark stars: an article on gravitational waves and boson stars

Maths on the Move, is the podcast from plus.maths.org. We speak to researchers from the frontiers of mathematical science so you can connect with the maths that shapes and explains our world. Hosted by Plus editors Rachel Thomas and Marianne Freiberger.

Plus is based at the Maths Faculty at the University of Cambridge so we have lots of opportunities to talk to interesting mathematicians about their work and their working lives. This week we speak to Holly Krieger, who is a professor here in a podcast that we originally produced for the Maths Faculty.



Holly works in the overlap of two areas of mathematics: number theory – which is famous for problems such as Fermat's Last Theorem – and complex dynamics, which gives rise to beautiful fractals. This intersection is known as arithmetic dynamics and it's an exciting, relatively young area of research. Holly's work has been very successful, being awarded several prestigious prizes. And she is also known for her appearances on the Numberphile channel where she has shared the beauty of maths in a range of areas, from centrifuge to the Mandelbrot set.



Holly told us about how she came to her current research, the benefits of a career in maths, advice for younger mathematicians, and her appearances on Numberphile.



Find out more about:



Holly's work


Number theory


Fermat's Last Theorem


Mandelbrot set


Holly's appearances on Numberphile



Maths on the Move, is the podcast from plus.maths.org. We speak to researchers from the frontiers of mathematical science so you can connect with the maths that shapes and explains our world. Hosted by Plus editors Rachel Thomas and Marianne Freiberger.

Hannah Fry, Cambridge's first Professor of the Public Understanding of Mathematics, has been awarded the Leelavati Prize at this year's International Congress of Mathematicians (ICM). The Leelavati Prize is awarded every four years by the International Mathematical Union and Infosys for outstanding contributions for increasing public awareness of mathematics.

We talked to Hannah in the run-up to the ICM about how she feels about being awarded the prize, the role of mathematics in culture, and her favourite experience as a maths communicator.

As Hannah puts it, "I feel as though there are these wonderful secrets that are completely invisible to almost everybody in the world who are mathematicians and it doesn’t make sense to me we would keep them to ourselves — I feel as though I have this really good bit of gossip that I just want to share."

To hear Hannah talk about her favourite mathematical moment, which is mentioned in this episode, see this podcast recorded when she became Professor of the Public Understanding of Mathematics at the University of Cambridge.

You can see the part of Hannah Fry's RI Christmas lecture mentioned in this podcast on YouTube.

The photo of Hannah is courtesy of the Simons Foundation.

Maths on the Move, is the podcast from plus.maths.org. We speak to researchers from the frontiers of mathematical science so you can connect with the maths that shapes and explains our world. Hosted by Plus editors Rachel Thomas and Marianne Freiberger.

We are continuing our conversations with mathematician colleagues at the University of Cambridge, part of the podcast we produce for the Maths Faculty here. Today we meet Julian Sahasrabudhe, Professor of Mathematics, and one of the invited speakers at the International Congress of Mathematicians (ICM) in July this year.

The ICM is one of the biggest events in the mathematics world and is the host of several prizes, including the prestigious Fields Medal. Only mathematicians at the very forefront of research are invited to speak, so we were very excited to learn more about Julian's work.

We spoke to him about his path into mathematics, from his childhood dreams to his early career as a drummer, before he finally settled on maths. Julian also gave us a brief introduction to his work in the field of combinatorics and how it offers partnerships with other areas of maths.

The podcast mentions Maryna Viazovska, who won a Fields Medal in 2022. Julian discusses the link between Ramsey theory and her work on sphere packing, as in the image below (courtesy Greg A L, CC BY-SA 3.0).

Find out more about:

Julian's work and its connections to sphere packings

Combinatorics

Other Cambridge mathematicians invited to speak at the 2026 ICM

The 2022 ICM

Maths on the Move, is the podcast from plus.maths.org. We speak to researchers from the frontiers of mathematical science so you can connect with the maths that shapes and explains our world. Hosted by Plus editors Rachel Thomas and Marianne Freiberger.

We are very lucky to be based at the Centre for Mathematical Sciences at the University of Cambridge. To start our latest podcast season we bring you a series of conversations with our mathematician colleagues, part of the podcast we produce for the Maths Faculty here.

In our first podcast we meet Richard Samworth, Professor of Statistical Science and Director of the Statistical Laboratory. We spoke to him in the run up to the International Congress of Mathematicians (ICM), one of the biggest dates in the mathematical calendar, where the most prestigious prizes in maths, including the Fields Medals, are awarded. Held every four years, the ICM features the world's leaders in the field and celebrates the diversity of today’s mathematics. Only mathematicians whose work is of the highest international standard are invited to speak at the week-long event, and Richard is one of the invited speakers at the ICM this July!

Richard's contributions to statistics have been recognised with numerous honours and awards. In 2025, he won two prestigious prizes in the space of 24 hours – the David Cox Medal for Statistics and the Guy Medal in Silver.

We talked to Richard to find out more about the work he will be speaking about at the ICM, how his field of statistics is simultaneously very theoretical and very applied, and what he most values about being part of the mathematical community here in Cambridge.

Find out more about:

Richard's work

Other Cambridge mathematicians invited to speak at the 2026 ICM

The 2022 ICM

The history of the ICM

Maths on the Move, is the podcast from plus.maths.org. We speak to researchers from the frontiers of mathematical science so you can connect with the maths that shapes and explains our world. Hosted by Plus editors Rachel Thomas and Marianne Freiberger.